function getFileBase64(file) {
    return new Promise((resolve, reject) => {
    let reader = new FileReader();
    reader.readAsDataURL(file);
    reader.onload = function (e) {
    let res = e.target.result.split(',')[1]
    // 转换已经完成
    resolve(res);
    };
    })
   }
   export default getFileBase64;